1) Given a directed graph (n vertices, m edges), return a topological ordering if one exists. If the graph contains a cycle, detect it and explain how your approach identifies the cycle. Implement and compare both Kahn’s algorithm (BFS with in-degree) and a DFS-based approach; analyze time and space complexity, and discuss how to handle multiple valid orderings. 2) Given a lowercase string text and a lowercase string pattern, return all starting indices of substrings in text that are permutations of pattern. Achieve O(n) time using a fixed-size sliding window with character counts; handle repeated characters and edge cases (empty pattern, pattern longer than text).